U.S. patent application number 13/733690 was filed with the patent office on 2014-03-06 for driving device of display device.
This patent application is currently assigned to Samsung Display Co., Ltd.. The applicant listed for this patent is SAMSUNG DISPLAY CO., LTD.. Invention is credited to Won Tae Kim, Ok-Kwon Shin, Sun Kyu Son.
Application Number | 20140062985 13/733690 |
Document ID | / |
Family ID | 50186895 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140062985 |
Kind Code |
A1 |
Shin; Ok-Kwon ; et
al. |
March 6, 2014 |
DRIVING DEVICE OF DISPLAY DEVICE
Abstract
A driving device of a display apparatus includes: a gate driver,
a gate on voltage modulator, and a signal controller. The gate
driver includes a plurality of gate driving circuits, each of the
gate driving circuits being configured to: generate a gate signal
according to a gate control signal, and apply the gate signal to at
least one gate line. The gate on voltage modulator is configured
to: modulate a gate on voltage according to a modulation control
signal, and generate a first modulated gate on voltage. The signal
controller is configured to generate the modulation control signal
and the gate control signal. At least one of the plurality of gate
driving circuits includes an amplifier configured to: receive the
first modulated gate on voltage, and output a second modulated gate
on voltage including substantially the same waveform as the first
modulated gate on voltage.
Inventors: |
Shin; Ok-Kwon; (Asan-si,
KR) ; Kim; Won Tae; (Cheongju-si, KR) ; Son;
Sun Kyu; (Suwon-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG DISPLAY CO., LTD. |
Yongin-city |
|
KR |
|
|
Assignee: |
Samsung Display Co., Ltd.
Yongin-city
KR
|
Family ID: |
50186895 |
Appl. No.: |
13/733690 |
Filed: |
January 3, 2013 |
Current U.S.
Class: |
345/212 |
Current CPC
Class: |
G09G 3/3696 20130101;
G09G 3/3677 20130101; G09G 2320/0247 20130101 |
Class at
Publication: |
345/212 |
International
Class: |
G09G 3/36 20060101
G09G003/36 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 3, 2012 |
KR |
10-2012-0097229 |
Claims
1. A driving device of a display apparatus, comprising: a gate
driver comprising a plurality of gate driving circuits, each of the
gate driving circuits being configured to: generate a gate signal
according to a gate control signal, and apply the gate signal to at
least one gate line; a gate on voltage modulator configured to:
modulate a gate on voltage according to a modulation control
signal, and generate a first modulated gate on voltage; and a
signal controller configured to generate the modulation control
signal and the gate control signal, wherein at least one of the
plurality of gate driving circuits comprises an amplifier
configured to: receive the first modulated gate on voltage, and
output a second modulated gate on voltage comprising substantially
the same waveform as the first modulated gate on voltage.
2. The driving device of a display apparatus of claim 1, further
comprising: a gate signal generator configured to: receive the
second modulated gate on voltage, generate the gate signal
comprising a gate off voltage and at least one gate on pulse, and
output the generated gate signal to the at least one gate line.
3. The driving device of a display apparatus of claim 2, wherein:
each of the plurality of gate driving circuits is configured to
receive a corresponding first modulated gate on voltage; and each
of the corresponding first modulated gate on voltages respectively
input to the plurality of gate driving circuits comprises
substantially the same waveform.
4. The driving device of a display apparatus of claim 3, wherein:
the amplifier comprises: a first power terminal configured to
receive the gate on voltage, and a second power terminal configured
to receive the gate off voltage; and a high level of the first
modulated gate on voltage is lower than the gate on voltage input
to the first power terminal of the amplifier.
5. The driving device of a display apparatus of claim 4, further
comprising: a data driving circuit configured to apply at least one
data voltage to at least one data line, wherein the high level of
the first modulated gate on voltage is lower than the gate on
voltage input to the first power terminal of the gate driving
circuit disposed farthest away from the data driving circuit.
6. The driving device of a display apparatus of claim 5, wherein:
the first modulated gate on voltage comprises a down pulse that
descends from the high level to a low voltage in synchronization
with the modulation control signal.
7. The driving device of a display apparatus of claim 6, wherein:
the low voltage comprises a value between the gate on voltage and
the gate off voltage.
8. The driving device of a display apparatus of claim 7, wherein:
the gate signal generator is configured to generate the gate signal
based on at least one gate clock signal.
9. The driving device of a display apparatus of claim 1, wherein
the amplifier comprises: a first power terminal configured to
receive a gate on voltage, and a second power terminal configured
to receive a gate off voltage; and a high level of the first
modulated gate on voltage is lower than the gate on voltage input
to the first power terminal of the amplifier.
10. The driving device of a display apparatus of claim 9, further
comprising: a data driving circuit configured to apply at least one
data voltage to at least one data line, wherein the high level of
the first modulated gate on voltage is lower than the gate on
voltage input to the first power terminal of the gate driving
circuit disposed farthest away from the data driving circuit.
11. A driving device of a display apparatus, comprising: a gate
driver comprising a plurality of gate driving circuits, each of the
plurality of gate driving circuits being configured to: generate a
gate signal according to a gate control signal, and apply the gate
signal to at least one gate line; and a signal controller
configured to generate the gate control signal, wherein at least
one of the plurality of gate driving circuits comprises a gate on
voltage modulator configured to generate a modulated gate on
voltage based on modulation of a gate on voltage according to a
modulation control signal.
12. The driving device of a display apparatus of claim 11, further
comprising: a gate signal generator configured to: receive the
modulated gate on voltage, generate the gate signal comprising a
gate off voltage and at least one gate on pulse, and output the
generated gate signal to the at least one gate line.
13. The driving device of a display apparatus of claim 12, wherein
the gate on voltage modulator includes: a first transistor; a
second transistor connected to the first transistor; a modulation
controller configured to control the first and second transistors
according to the modulation control signal; and an amplifier
comprising: an input terminal configured to receive a low voltage
comprising a value between the gate on voltage and the gate off
voltage, and an output terminal connected to the second
transistor.
14. The driving device of a display apparatus of claim 13, wherein:
when the modulation control signal is in a first state, the first
transistor is turned-on, the second transistor is turned-off, and
the gate on voltage is output to the gate signal generator; and
when the modulation control signal is in a second state different
from the first state, the first transistor is turned-off, the
second transistor is turned-on, and a down pulse that descends from
the gate on voltage is output to the gate signal generator.
15. The driving device of a display apparatus of claim 14, further
comprising: a variable resistor connected between the second
transistor and the amplifier.
16. The driving device of a display apparatus of claim 15, wherein:
the gate signal generator is connected to a contact point between
the first transistor and the second transistor.
17. The driving device of a display apparatus of claim 16, wherein
the gate signal generator is configured to generate the gate signal
based on at least one gate clock signal.
18. The driving device of a display apparatus of claim 13, further
comprising: a variable resistor connected between the second
transistor and the amplifier.
19. The driving device of a display apparatus of claim 13, wherein
the gate signal generator is connected to a contact point between
the first transistor and the second transistor.
20. The driving device of a display apparatus of claim 11, wherein:
the signal controller is further configured to generate the
modulation control signal; and the gate on voltage modulator is
further configured to receive the modulation control signal from
the signal controller.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from and the benefit of
Korean Patent Application No. 10-2012-0097229, filed on Sep. 3,
2012, which is incorporated by reference for all purposes as if set
forth herein.
BACKGROUND
[0002] 1. Field
[0003] Exemplary embodiments relate to display technology, and more
particularly to driving devices for display devices.
[0004] 2. Discussion
[0005] In general, a display device includes a plurality of pixels
(i.e., units for displaying images) and a plurality of drivers
configured to drive the plurality of pixels.
[0006] Individual ones of the plurality of pixels are connected
with corresponding ones of a plurality of gate lines and data
lines. Each pixel may include a switching element, such as a thin
film transistor, connected to corresponding ones of the plurality
of gate lines and data lines. At least one pixel electrode is
typically connected thereto. The plurality of gate lines and data
lines may extend in different directions, and may cross each other,
such as in a perpendicular (or substantially perpendicular)
manner.
[0007] The plurality of drivers usually include a data driver
configured to apply one or more data voltages to the plurality of
data lines, a gate driver configured to apply one or more gate
signals to the plurality of gate lines, and a signal controller
configured to apply one or more control signals to the gate driver
and the data driver to, thereby, control the gate driver and the
data driver. In this manner, the signal controller is configured to
control driving timings of the gate driver and the data driver, as
well as configured to supply an image signal to the data
driver.
[0008] The gate driver may include a shift register that, in turn,
includes a plurality of stages that are subordinately connected to
each other or at least one gate driving circuit. The gate driver is
configured to receive a plurality of driving voltages and a
plurality of gate control signals to generate gate signals. The
plurality of driving voltages may include a gate on voltage
configured to turn on corresponding switching elements and a gate
off voltage configured to turn off the corresponding switching
elements. The plurality of gate control signals may include a
scanning start signal STV configured to instruct a scanning start,
a gate clock signal CPV configured to control an output timing of a
gate on pulse, and the like. The gate driver is configured to
output gate on pulses to the plurality of gate lines in
sequence.
[0009] The data driver is configured to apply the plurality of data
voltages to the plurality of data lines whenever a gate on pulse is
applied to a gate line so that a corresponding data voltage may be
applied to a respective pixel via a corresponding switching
element.
[0010] When the gate off voltage is applied to the thin film
transistor, which is the switching element of each pixel, to turn
off the thin film transistor, a voltage applied to each pixel may
be changed according to one or more corresponding voltage changes
associated with a parasitic capacitor of the thin film transistor
and the gate signal. The voltage change is referred to as a
kickback voltage. A flicker and/or other image distortions may be
caused by deviations in the kickback voltage and, as such, image
quality may be deteriorated. As a size of the display device
becomes larger, a data charging time of the thin film transistor
may be insufficient due to a delay of the gate on pulse caused by a
load of the gate line. This too may cause image distortions or
degradations.
[0011] Conventionally, the above-noted problems have been addressed
by modifying the gate on voltage to generate the plurality of gate
signals.
[0012] As display panels of display devices become larger, signal
wires (or lines) configured to transfer the plurality of driving
voltages and the plurality of gate control signals input to the
gate driver are becoming longer and, as such, distortion in
waveforms of the plurality of driving voltages and the plurality of
gate control signals may result due to the load on the plurality of
signal wires. As a result, a deviation in a level and a waveform of
a gate on pulse may occur according to a position of the gate
driving circuit, and a boundary between display areas corresponding
to two gate driving circuits may be perceived by an observer. As
such, image quality of the display device may become
deteriorated.
[0013] Therefore, there is a need for an approach that provides
efficient, cost effective techniques to drive display devices that
can reduce (or otherwise prevent) deviations in the waveforms of
gate-on pulses and, thereby, reduce (or otherwise prevent) image
quality distortions or degradations.
[0014] The above information disclosed in this Background section
is only for enhancement of understanding of the background of the
invention and, therefore, it may contain information that does not
form any part of the prior art nor what the prior art may suggest
to a person of ordinary skill in the art.
SUMMARY
[0015] Exemplary embodiments provide a driving device of a display
apparatus and an associated method to drive the display apparatus,
which is configured to prevent (or otherwise reduce) deviations in
a waveform of a gate on pulse output from a plurality of gate
driving circuits and, thereby, configured to prevent (or otherwise
reduce) image quality deteriorations.
[0016] Additional aspects will be set forth in the detailed
description which follows and, in part, will be apparent from the
disclosure, or may be learned by practice of the invention.
[0017] According to exemplary embodiments, a driving device of a
display apparatus includes: a gate driver, a gate on voltage
modulator, and a signal controller. The gate driver includes a
plurality of gate driving circuits, each of the plurality of gate
driving circuits being configured to: generate a gate signal
according to a gate control signal, and apply the gate signal to at
least one gate line. The gate on voltage modulator is configured
to: modulate a gate on voltage according to a modulation control
signal, and generate a first modulated gate on voltage. The signal
controller is configured to generate the modulation control signal
and the gate control signal. At least one of the plurality of gate
driving circuits includes an amplifier configured to: receive the
first modulated gate on voltage, and output a second modulated gate
on voltage including substantially the same waveform as the first
modulated gate on voltage.
[0018] According to exemplary embodiments, a driving device of a
display apparatus includes: a gate driver and a signal controller.
The gate driver includes a plurality of gate driving circuits, each
of the plurality of gate driving circuits is configured to:
generate a gate signal according to a gate control signal, and
apply the gate signal to at least one gate line. The signal
controller is configured to generate the gate control signal. At
least one of the plurality of gate driving circuits includes a gate
on voltage modulator configured to generate a modulated gate on
voltage based on modulation of a gate on voltage according to a
modulation control signal.
[0019] According to exemplary embodiments, a method to drive a
display apparatus includes: receiving, at a gate driving circuit, a
first modulated gate on voltage signal; receiving, at the gate
driving circuit, a modified gate on voltage modified based on a
spatial disposition of the gate driving circuit with respect to at
least one other gate driving circuit; generating, based on the
first modulated gate on voltage signal and a feedback voltage
signal, a second modulated gate on voltage signal exhibiting a
substantially similar waveform as the first modulated gate on
voltage signal; and generating, based on the second modulated gate
on voltage signal, at least one gate signal.
[0020] According to exemplary embodiments, a method to drive a
display apparatus includes: receiving a modulation control signal
comprising a high level and a low level; receiving a gate on
voltage; receiving another voltage comprising a value between the
gate on voltage and a gate off voltage, wherein when the modulation
control signal is at the high level, the method further comprises:
utilizing the gate on voltage to generate at least a portion of a
gate signal, and wherein when the modulation control signal is at
the low level, the method further comprises: utilizing a down pulse
between the gate on voltage and the another voltage to generate at
least another portion of the gate signal.
[0021] According to exemplary embodiments, it is possible to
prevent (or otherwise reduce) deviations in a waveform of a gate on
pulse according to a position of a gate driving circuit and,
thereby, prevent (or otherwise reduce) distortions and/or
degradations in image quality of an associated display
apparatus.
[0022] The foregoing general description and the following detailed
description are exemplary and explanatory and are intended to
provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate exemplary
embodiments of the invention, and together with the description
serve to explain the principles of the invention.
[0024] FIG. 1 is a block diagram of a display apparatus, according
to exemplary embodiments.
[0025] FIG. 2 is a layout view of the display apparatus of FIG. 1,
according to exemplary embodiments.
[0026] FIG. 3 is a block diagram of a gate driving circuit of a
driving device of the display apparatus of FIG. 1, according to
exemplary embodiments.
[0027] FIG. 4 is a waveform diagram of a plurality of gate on
voltages input to a plurality of gate driving circuits and a
plurality of modified gate on voltages, according to exemplary
embodiments.
[0028] FIG. 5 is a timing diagram of various driving signals,
according to exemplary embodiments.
[0029] FIG. 6A is a graph of a conventional output waveform of a
gate driving circuit.
[0030] FIG. 6B is an enlarged graph of portion A of FIG. 6A.
[0031] FIG. 6C is an enlarged graph of portion B of FIG. 6A.
[0032] FIG. 7A is a graph of an output waveform of a gate driving
circuit, according to exemplary embodiments.
[0033] FIG. 7B is an enlarged graph of portion A of FIG. 7A,
according to exemplary embodiments.
[0034] FIG. 7C is an enlarged graph of portion B of FIG. 7A,
according to exemplary embodiments.
[0035] FIG. 8 is a block diagram of a display apparatus, according
to exemplary embodiments.
[0036] FIG. 9 is a block diagram of a gate driving circuit of a
driving device of the display device of FIG. 8, according to
exemplary embodiments.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0037] In the following description, for the purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of various exemplary embodiments.
It is apparent, however, that various exemplary embodiments may be
practiced without these specific details or with one or more
equivalent arrangements. In other instances, well-known structures
and devices are shown in block diagram form in order to avoid
unnecessarily obscuring various exemplary embodiments.
[0038] In the accompanying figures, the size and relative sizes of
layers, films, panels, regions, etc., may be exaggerated for
clarity and descriptive purposes. Also, like reference numerals
denote like elements.
[0039] When an element or layer is referred to as being "on,"
"connected to," or "coupled to" another element or layer, it may be
directly on, connected to, or directly coupled to the other element
or layer or intervening elements or layers may be present. When,
however, an element or layer is referred to as being "directly on,"
"directly connected to," or "directly coupled to" another element
or layer, there are no intervening elements or layers present. For
the purposes of this disclosure, "at least one of X, Y, and Z" and
"at least one selected from the group consisting of X, Y, and Z"
may be construed as X only, Y only, Z only, or any combination of
two or more of X, Y, and Z, such as, for instance, XYZ, XYY, YZ,
and ZZ. Like numbers refer to like elements throughout. As used
herein, the term "and/or" includes any and all combinations of one
or more of the associated listed items.
[0040] Although the terms first, second, etc. may be used herein to
describe various elements, components, regions, layers and/or
sections, these elements, components, regions, layers and/or
sections should not be limited by these terms. These terms are only
used to distinguish one element, component, region, layer or
section from another region, layer or section. Thus, a first
element, component, region, layer or section discussed below could
be termed a second element, component, region, layer or section
without departing from the teachings of the present disclosure.
[0041] Spatially relative terms, such as "beneath," "below,"
"lower," "above," "upper," and/or the like, may be used herein for
descriptive purposes and, thereby, to describe one element or
feature's relationship to another element(s) or feature(s) as
illustrated in the drawings. Spatially relative terms are intended
to encompass different orientations of an apparatus in use or
operation in addition to the orientation depicted in the drawings.
For example, if the apparatus in the drawings is turned over,
elements described as "below" or "beneath" other elements or
features would then be oriented "above" the other elements or
features. Thus, the exemplary term "below" can encompass both an
orientation of above and below. Furthermore, the apparatus may be
otherwise oriented (e.g., rotated 90 degrees or at other
orientations) and, as such, the spatially relative descriptors used
herein interpreted accordingly.
[0042] The terminology used herein is for the purpose of describing
particular embodiments and is not intended to be limiting. As used
herein, the singular forms, "a," "an," and "the" are intended to
include the plural forms as well, unless the context clearly
indicates otherwise. Moreover, the terms "comprises" and/or
"comprising," when used in this specification, specify the presence
of stated features, integers, steps, operations, elements, and/or
components, but do not preclude the presence or addition of one or
more other features, integers, steps, operations, elements,
components, and/or groups thereof.
[0043] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
disclosure is a part. Terms, such as those defined in commonly used
dictionaries, should be interpreted as having a meaning that is
consistent with their meaning in the context of the relevant art
and will not be interpreted in an idealized or overly formal sense,
unless expressly so defined herein.
[0044] FIG. 1 is a block diagram of a display apparatus, according
to exemplary embodiments.
[0045] Referring to FIG. 1, the display apparatus includes a
display panel 300 and a driving device configured to drive the
display panel 300. The driving device includes a gate driver 400, a
data driver 500, a driving voltage generator 700, a gate on voltage
modulator 800, and a timing (or signal) controller 600.
[0046] The display panel 300 may be (or include) a flat panel
display (FPD), such as: a liquid crystal display (LCD), an organic
light emitting diode (OLED) display, an electrophoretic display
(EPD), an electrowetting display (EWD), a plasma display (PD), a
field emission display (FED), etc. In the case of a liquid crystal
display, the display panel 300 may include lower and upper panels
(not illustrated) facing each other and a liquid crystal layer (not
illustrated) disposed between the lower and upper panels, such as
when viewed in a cross-sectional nature.
[0047] According to exemplary embodiments, the display panel 300
includes a plurality of signal lines and a plurality of pixels PX
respectively connected to the plurality of signal lines. The
plurality of pixels PX may be arranged in a matrix (or
substantially matrix) form; however, other arrangements are
contemplated and may be utilized.
[0048] The signal lines include a plurality of gate lines G1-Gn
configured to transfer gate signals (also referred to as scanning
signals) and a plurality of data lines D1-Dm configured to transfer
data voltages.
[0049] Each pixel PX may include at least one switching element
(not shown) connected to a corresponding one of the plurality of
gate lines G1-Gn and a corresponding one of the plurality of data
lines D1-Dm. At least one pixel electrode (not illustrated) may be
connected to the corresponding one of the plurality of gate lines
G1-Gn and the corresponding one of the plurality of data lines
D1-Dm. The switching element may be (or include) at least one thin
film transistor (not shown), and may be turned on or off according
to an applied gate signal transferred by the corresponding gate
line of the plurality of gate lines G1-Gn and, thereby, configured
to selectively apply a data voltage transferred by the
corresponding one of the plurality of data lines D1-Dm to the at
least one pixel electrode. Each pixel PX may be configured to
display an image including a corresponding luminance according to
the data voltage applied to the at least one pixel electrode. It is
also contemplated that the display apparatus may include one or
more common electrodes (not illustrated), which may be associated
with the plurality of pixels PX. Furthermore, the at least one
pixel electrode and the one or more common electrodes may be
suitably patterned, interlaced, and/or overlapped by one
another.
[0050] To implement a color display, each pixel PX may be
configured to display one of a plurality of primary colors (spatial
division) or each pixel PX may alternately be configured to display
one or more of the plurality of primary colors within a time window
(temporal division) to, thereby, achieve a desired color by the
spatial and temporal sum of the one or more presented primary
colors. An example of the plurality of primary colors may include,
for instance, three primary colors: such as red, green, and blue;
however, it is contemplated that any number and/or range of colors
may be utilized, whether primary or not. In exemplary embodiments,
a plurality of adjacently disposed pixels PX that are configured to
display different primary (or other) colors may be configured to
form one set (referred to as one dot) together. One dot may be
configured to display a white image.
[0051] The gate driver 400 is connected to the plurality of gate
lines G1-Gn of the display panel 300. The gate driver 400 is
configured to receive a gate control signal CONT1 from the signal
controller 600, receive a modulated gate on voltage VGPM_S from the
gate on voltage modulator 800, and receive a gate on voltage Von
and a gate off voltage Voff from the driving voltage generator 700.
In this manner, the gate driver 400 is further configured to
generate a plurality of gate signals including gate on pulses based
on the received signals/voltages and, thereby, configured to
sequentially apply the plurality of gate signals to the plurality
of gate lines G1-Gn.
[0052] The modulated gate on voltage VGPM_S may include a modified
gate on voltage that is the same as or lower than the gate on
voltage Von, as well as include a down pulse that is periodically
shown. The down pulse may have a form that descends for a
predetermined time from the modified gate on voltage to a "low"
voltage that is lower than the modified gate on voltage, but higher
than the gate off voltage Voff. However, the modulated gate on
voltage VGPM_S is not limited thereto and may be (or include)
various additional and/or alternative waveforms according to one or
more conditions of the display panel 300.
[0053] For descriptive purposes, exemplary embodiments are
described in association with an example in which the modulated
gate on voltage VGPM_S includes a high level, that is, a modified
gate on voltage, and a down pulse descending to a low voltage Vlow
that is lower than the modified gate on voltage, but higher than
the gate off voltage Voff.
[0054] The gate signal includes a gate off voltage Voff configured
to turn off a switching element of a pixel PX, and at least one
gate on pulse configured to turn on the switching element of the
pixel PX. The gate on pulse may have a form that descends to the
gate off voltage Voff from the low voltage Vlow that is descended
from a high level voltage, that is, the modified gate on voltage of
the modulated gate on voltage VGPM_S.
[0055] The gate control signal CONT1 includes a scanning start
signal STV configured to instruct a scanning start of the gate
signal, a gate clock signal CPV configured to control an output
timing of the gate on pulse of the gate signal, at least one low
voltage, and/or the like.
[0056] The data driver 500 is connected to the plurality of data
lines D1-Dm of the display panel 300. The data driver 500 is
configured to receive a data control signal CONT2 and an output
image signal DAT from the signal controller 600, as well as
configured to select a gray voltage corresponding to each output
image signal DAT to convert the output image signal DAT to a data
voltage, which is an analog data signal. The data control signal
CONT2 includes a horizontal synchronization start signal configured
to notify a transmission start of the output image signal DAT to
those pixels PX in one row, a load signal configured to instruct
that the data voltage is to be applied to the plurality of data
lines D1-Dm, a data clock signal, and/or the like. The data control
signal CONT2 may further include an inversion signal configured to
invert a polarity of the data voltage for a common voltage Vcom
(referred to as a polarity of the data voltage).
[0057] The data driver 500 is configured to supply a data voltage
for a one (1) horizontal period to each of the plurality of data
lines D1-Dm every one (1) horizontal period 1H when a gate on pulse
is applied to each of the plurality of gate lines G1-Gn. In this
manner, the data driver 500 may supply the data voltage to each of
the plurality of data lines D1-Dm in response to an output enable
signal DE.
[0058] The driving voltage generator 700 is configured to generate
one or more driving voltages, such as a gate on voltage Von, a gate
off voltage Voff, and a low voltage Vlow and, thereby, configured
to supply the gate on voltage Von and the gate off voltage Voff to
the gate driver 400, and the gate on voltage Von and the low
voltage Vlow to the gate on voltage modulator 800. In addition, one
or more driving voltages may be supplied to the data driver 500 and
the signal controller 600.
[0059] The gate on voltage modulator 800 is configured to receive a
modulation control signal KB from the signal controller 600 and to
receive the gate on voltage Von and the low voltage Vlow from the
driving voltage generator 700 and, thereby, configured to modulate
the gate on voltage Von to generate a modulated gate on voltage
VGPM_S. The modulated gate on voltage VGPM_S is supplied to the
gate driver 400.
[0060] The signal controller 600 is configured to receive an input
image signal IDAT and an input control signal ICON from a signal
source and to generate various kinds of control signals to,
thereby, control the gate driver 400, the data driver 500, the gate
on voltage modulator 800, and the like.
[0061] According to exemplary embodiments, the respective driving
devices may be directly installed on the display panel 300 in at
least one IC chip form, adhered to the display panel 300 in a tape
carrier package (TCP) form, or installed on a printed circuit board
(not illustrated) that is to be connected to the display panel
300.
[0062] In exemplary embodiments, the gate driver 400, the data
driver 500, the signal controller 600, the gate on voltage
modulator 800, and/or the driving voltage generator 700 may be
implemented via one or more general purpose and/or special purpose
components, such as one or more discrete circuits, digital signal
processing chips, integrated circuits, application specific
integrated circuits, microprocessors, processors, programmable
arrays, field programmable arrays, instruction set processors,
and/or the like.
[0063] In association with driving the display apparatus, the
signal controller 600 is configured to receive an input image
signal IDAT and an input control signal ICON from, for instance, a
signal source configured to control a display of the display
apparatus. The input image signal IDAT includes luminance
information associated with each pixel PX, and the luminance
information includes (or is associated with) a predetermined number
of grays (or gray scales). To this end, the input control signal
ICON may be (or include) a vertical synchronization signal, a
horizontal synchronizing signal, a main clock signal, a data enable
signal, and/or the like.
[0064] The signal controller 600 is configured to process the input
image signal IDAT based on the input image signal IDAT and the
input control signal ICON to, thereby, convert the processed input
image signal IDAT into an output image signal DAT and generate a
gate control signal CONT1, a data control signal CONT2, and a
modulation control signal KB. The signal controller 600 may
transmit the gate control signal CONT1 to the gate driver 400,
transmit the data control signal CONT2 and the output image signal
DAT to the data driver 500, and transmit the modulation control
signal KB to the gate on voltage modulator 800.
[0065] Accordingly, the data driver 500 is configured to receive
the output image signal DAT for pixels PX in one row according to
the data control signal CONT2 received from the signal controller
600, as well as configured to select a gray voltage corresponding
to each output image signal DAT to, thereby, convert the output
image signal DAT into an analog data voltage and apply the output
image signal DAT to the corresponding plurality of data lines
D1-Dm.
[0066] The gate driver 400 is configured to sequentially apply one
or more gate on pulses to the plurality of gate lines G1-Gn
according to the gate control signal CONT1 received from the signal
controller 600 and, thereby, to turn on corresponding switching
elements connected to the plurality of gate lines G1-Gn. The data
voltage applied to the plurality of data lines D1-Dm is applied to
the corresponding pixels PX via "turned-on" switching elements.
When the data voltage is applied to a "tuned-on" pixel PX, the
pixel PX may display luminance corresponding to the data voltage
via various optical conversion elements (not shown). For example,
in the case of a liquid crystal display, luminance corresponding to
a gray scale of the input image signal IDAT may be displayed via
control of an inclined degree (or rotation) of liquid crystal
molecules of the liquid crystal layer and, thereby, control of the
polarization of light or other form of illumination utilized in
association with the presentation of an image via the pixel.
[0067] While the process is repeated by setting a one (1)
horizontal period 1H as a unit, gate-on voltages Von are
sequentially applied to all of the plurality of gate lines G1-Gn
and data voltages are applied to all of the plurality of pixels PX
to, thereby, display one or more image associated with one
frame.
[0068] A driving device, e.g., a gate driver, of the display
apparatus of FIG. 1 is described in more detail in association with
FIGS. 2-4.
[0069] FIG. 2 is a layout view of the display apparatus of FIG. 1,
according to exemplary embodiments. FIG. 3 is a block diagram of a
gate driving circuit of a driving device of the display apparatus,
according to exemplary embodiments. FIG. 4 is a waveform diagram of
a plurality of gate on voltages input to a plurality of gate
driving circuits and a plurality of modified gate on voltages,
according to exemplary embodiments.
[0070] Referring to FIG. 2, the gate driver 400, according to
exemplary embodiments, includes at least one gate driving circuit,
such as gate driving circuits 450_1, 450_2, and 450_3. The
respective gate driving circuits 450_1, 450_2, and 450_3 may be
configured in at least one IC chip form. Although FIG. 2
illustrates a gate driver 400 including three gate driving circuits
450_1, 450_2, and 450_3, it is contemplated that any suitable
number of gate driving circuits may be utilized. As shown, however,
the gate driving circuits 450_1, 450_2, and 450_3 may be installed
on the display panel 300 including a display area DA, the display
area DA being an area of the display panel 300 configured to
present images to an observer. Alternatively or additionally, the
gate driving circuits 4501_1, 450_2, 450_3 may be installed on a
printed circuit board (not illustrated) connected to the display
panel 300.
[0071] The plurality of gate driving circuits 450_1, 450_2, and
450_3 is arranged in a line and each of the gate driving circuits
450_1, 450_2, and 450_3 are connected to a respective set of gate
lines, e.g., a gate line set including gate lines G1_1-Ga_1,
G1_2-Ga_2, and G1_3-Ga_3, which is driven by the respective gate
lines. It is noted that "a" corresponds to a real integer. In this
manner, although the illustrated exemplary embodiment depicts the
same number of gate lines G1-Gn connected to the respective driving
circuits 450_1, 450_2, and 450_3, it is contemplated that any
suitable number of gate lines may be associated with the driving
circuits 450_1, 450_2, and 450_3 and each driving circuit may be
associated with a different number of gate lines than one or more
of the other driving circuits.
[0072] According to exemplary embodiments, the gate driving
circuits 450_1, 450_2, and 450_3 may be configured to receive
various driving signals, such as the gate on voltage Von, the gate
off voltage Voff, the modulated gate on voltage VGPM_S, and the
gate control signal CONT1, via a signal wiring line SL connected to
a data driving circuit 540 included as part of (or associated with)
the data driver 500 or a flexible printed circuit film installed on
the data driving circuit 540. In this manner, an amount (or degree)
of delay of an associated driving signal input to the respective
gate driving circuits 450_1, 450_2, and 450_3 may be different from
each other due to a load associated with resistors R1, R2, and R3
the signal wiring line SL. For example, levels of gate on voltages
Von input to the respective gate driving circuits 450_1, 450_2, and
450_3 may be lowered by a voltage drop along the signal wiring line
SL due to the presence of the resistors R1, R2, and R3, which may
be disposed between respective ones of the gate driving circuits
450_1, 450_2, and 450_3 or between one of the gate driving circuits
(e.g., gate driving circuit 450_1) and the data driving circuit
540.
[0073] Referring to FIG. 3, each of the gate driving circuits
450_1, 450_2, and 450_3 includes an amplifier 420 and a gate signal
generator 430. In order to avoid obscuring exemplary embodiments
described herein, the respective gate driving circuits 450_1,
450_2, and 450_3 will be collectively described in association with
a representative gate driving circuit 450.
[0074] According to exemplary embodiments, two power terminals of
the amplifier are configured to receive the gate on voltage Von and
the gate off voltage Voff, respectively, and a non-inversion input
terminal (e.g., the positive "+" terminal) is configured to receive
the modulated gate on voltage VGPM_S from, for instance, the gate
on voltage modulator 800, whereas an inversion input terminal
(e.g., the negative "-" terminal) is connected to an output
terminal to feedback an output voltage of the amplifier 420. The
modulated gate on voltage VGPM_S may include a down pulse that
periodically descends to a low voltage Vlow from a high level, that
is, a modified gate on voltage Von_S as described above.
[0075] Gate on voltages Von input to upper power terminals of the
respective gate driving circuits 450_1, 450_2, and 450_3 may be
different from each other according to respective positions of the
gate driving circuits 450_1, 450_2, and 450_3.
[0076] Referring to FIG. 4A, a first gate driving circuit 450_1 may
be configured to receive a gate on voltage Von of a first on level
Von1 that is lower than a level of the gate on voltage Von of the
data driving circuit 540. The difference between the first on level
Von1 and the gate on voltage Von may be the result of a voltage
drop associated with the resistor R1 disposed between the first
gate driving circuit 450_1 and the data driving circuit 540.
[0077] Referring to FIG. 4B, a second gate driving circuit 450_2
may be configured to receive a gate on voltage Von of a second on
level Von2 that is lower than the first on level Von1. The
difference between the first on level Von1 and the second on level
Von2 may be the result of a voltage drop associated with the
resistors R1 and R2 disposed between the second gate driving
circuit 450_2 and the data driving circuit 540.
[0078] Referring to FIG. 4C, a third gate driving circuit 450_3 may
be configured to receive a gate on voltage Von of a third on level
Von3 that is lower than the second on level Von2. The difference
between the second on level Von2 and the third on level Von3 may be
the result of a voltage drop associated with the resistors R1, R2,
and R3 disposed between the third gate driving circuit 450_3 and
the data driving circuit 540.
[0079] Adverting back to FIG. 3 and with continued reference to
FIG. 4, the gate off voltages Voff input to lower power terminals
of the respective amplifiers 420 of the gate driving circuits
450_1, 450_2, and 450_3 may have a first off level Voff1, a second
off level Voff2, and a third off level Voff3 that are respectively
lower in value, e.g., Voff1>Voff2>Voff3.
[0080] According to exemplary embodiments, the amplifier 420 is
configured to output a modulated gate on voltage VGPM exhibiting
the same waveform as the received modulated gate on voltage VGPM_S.
In this manner, the high level of the modulated gate on voltage
VGPM and the high level of the received modulated gate on voltage
VGPM_S may be set to become modified gate on voltages Von_S that
are lower than the gate on voltages Von received from the driving
voltage generator 700. As such, the modulated gate on voltage VGPM,
which is output by maintaining an offset of the gate on voltage Von
input to the upper power terminal of the amplifier 420, may exhibit
a predetermined high level for each respective gate driving circuit
450.
[0081] According to exemplary embodiments, a value of the modified
gate on voltage Von_S may be smaller than the third on level Von3
of the gate on voltage Von input to the "last" gate driving circuit
(e.g., third gate driving circuit 450_3) that is configured to
receive a gate on voltage Von including the lowest level.
Accordingly, as illustrated in FIG. 4, the high level of the
received modulated gate on voltage VGPM_S input to each of the gate
driving circuits 450_1, 450_2, and 450_3, that is, the modified
gate on voltage Von_S, may be lower than the lowest on level
voltage (e.g., the third on level Von3 voltage) among the levels of
the gate on voltages Von input to the gate driving circuits 450_1,
450_2, and 450_3. Further, since the received modulated gate on
voltage VGPM_S input to each of the gate driving circuits 450_1,
450_2, and 450_3 is input as a signal, the received modulated gate
on voltage VGPM_S will not be influenced by a signal delay due to
the resistor(s) of the signal wiring line SL and a load of a
parasitic capacitor, and/or the like. As a result, the high levels
of the modulated gate on voltages VGPM output by the amplifiers 420
of the gate driving circuits 450_1, 450_2, and 450_3 may be the
same as each other regardless of a difference between the power
levels input to the power terminal of each amplifier 420. In this
manner, the output waveforms thereof may also be the same as each
other.
[0082] In exemplary embodiments, the gate signal generator 430 is
configured to receive the modulated gate on voltage VGPM output
from the amplifier 420, as well as configured to receive the gate
off voltage Voff output from the driving voltage generator 700 and
the gate control signal CONT1, such as the gate clock signal CPV,
from the signal controller 600. Based on these received signals,
the gate signal generator 430 is configured to generate a plurality
of gate signals VG1_1-VGa_1 and apply the generated plurality of
gate signals VG1_1-VGa_1 respectively to the plurality of gate
lines G1_1-Ga-1 connected to the gate driving circuit 450. The
plurality of gate signals VG1_1-VGa_1 include a gate off voltage
Voff and at least one gate on pulse, and each gate on pulse may
include the high level of the modulated gate on voltage VGPM, that
is, the modified gate on voltage Von_S and the down pulse that
descends to the low voltage Vlow from the modified gate on voltage
Von_S.
[0083] A driving method of the display apparatus including one or
more gate driving circuits is described in more detail in
association with FIG. 5.
[0084] FIG. 5 is a timing diagram of various driving signals,
according to exemplary embodiments.
[0085] Referring to FIG. 5, the gate on voltage modulator 800 is
configured to receive the modulation control signal KB from the
signal controller 600. The modulation control signal KB may include
a down pulse represented by a one (1) horizontal period 1H. The
gate on voltage modulator 800 is configured to modulate a gate on
voltage Von to generate the modulated gate on voltage VGPM_S. The
modulated gate on voltage VGPM_S is configured to maintain the
modified gate on voltage Von_S while the modulation control signal
KB has a high level, and may include a down pulse that descends to
the low voltage Vlow in synchronization with the start of the down
pulse of the modulation control signal KB. In this manner, the
descent of the modulated gate on voltage VGPM_S to the low voltage
Vlow may occur over the duration of the time when the modulation
control signal KB exhibits the low level. The down pulse of the
modulated gate on voltage VGPM_S may also be represented by a one
(1) horizontal period 1H.
[0086] The generated modulated gate on voltage VGPM_S is input to
each gate driving circuit 450 of the gate driver 400. The gate
driving circuit 450 is configured to receive at least one gate
clock signal CPV from the signal controller 600 and, thereby,
configured to generate a gate signal based thereon. As seen in FIG.
5, the gate clock signal CPV includes a plurality of gate clock
signals (e.g., two gate clock signals CPV1 and CPV2) that are
inverted with one another. High levels or low levels of the two
gate clock signals CPV1 and CPV2 may be maintained for the 1
horizontal period 1H.
[0087] The gate driving circuit 450 may generate a gate signal
using the modulated gate on voltage VGPM including the same level
and waveform as the modulated gate on voltage VGPM_S as described
above. The gate driving circuit 450 may output at least one gate on
pulse including the modulated gate on voltage VGPM, while the input
gate clock signals CPV1 and CPV2 exhibit the high levels or the low
levels. To this end, the gate driving circuit 450 may output the
gate off voltage Voff for the remaining period of time. Each gate
on pulse may be output for an approximately one (1) horizontal
period 1H.
[0088] As such, a plurality of gate signals VG1, VG2, VG3, . . . ,
VGn may be configured to include gate on pulses that are
sequentially output to the plurality of gate lines G1-Gn connected
to the gate driving circuit 450.
[0089] According to exemplary embodiments, since the output
waveforms and levels of the modulated gate on voltage VGPM output
from the respective amplifiers 420 of each gate driving circuit 450
is the same (or substantially the same) as each other, waveforms
and levels of the gate on pulse of the gate signal output to the
plurality of gate lines G1-Gn by the plurality of gate driving
circuits 450 may be the same (or substantially the same) as each
other. Particularly, since a discharging path is connected to the
low power terminal of the respective amplifiers 420 when the down
pulse of the modulated gate on voltage VGPM is generated, gate on
pulses having the same waveform may be generated for each of the
plurality of gate driving circuits 450.
[0090] The effects of such a configuration and driving method will
be described with reference to FIGS. 6A-6C associated with a
conventional display apparatus and FIGS. 7A-7C associated with an
exemplary display apparatus, along with continued reference to FIG.
3.
[0091] FIG. 6A is a graph of a conventional output waveform of a
driving circuit. FIGS. 6B and 6C are enlarged graphs of respective
portions A and B of FIG. 6A. FIG. 7A is a graph of an output
waveform of a driving circuit, according to exemplary embodiments.
FIGS. 7B and 7C are enlarged graphs of respective portions A and B
of FIG. 7A, according to exemplary embodiments.
[0092] For example, when the gate driver 400 includes the first to
third gate driving circuits 450_1, 450_2, and 450_3, the first gate
driving circuit 450_1 is configured to output a gate signal VGi_1
to a first gate line Gi_1, the second gate driving circuit 450_2 is
configured to output a gate signal VGi_2 to a second gate line Gi_2
corresponding to the gate line Gi_1, and the third gate driving
circuit 450_3 is configured to output a gate signal VGi_3 to a
third gate line Gi_3 corresponding to the gate line Gi_1. In this
manner, a difference between gate signals output to the first and
third gate driving circuits 450_1 and 450_3, which are disposed
farthest away from each other is largest at a portion A where a
change in the gate signal is largest (for example, 197 mV, in a
conventional display apparatus, as seen in FIG. 6B). On the
contrary, a difference in a gate signal output between the gate
driving circuits 450_1, 450_2, and 450_3 may not be large at a
portion B where a change in the gate signal is small, e. g., 1 mV
in a conventional display apparatus, as seen in FIG. 6C.
[0093] Meanwhile, according to exemplary embodiments, as
illustrated in FIG. 7B, the difference in the gate signal output
between the first and third gate driving circuits 450_1 and 450_3
may not be large even at the portion A where the change of the gate
signal is large (for example, 8 mV). The value is not largely
different from the difference (about 1 mV) in the gate signal
output between the gate driving circuits 450_1, 450_2, and 450_3 at
the portion B where the change in the gate signal is small. There
is little difference in the gate signal output between the gate
driving circuits 450_1, 450_2, and 450_3 even at the portion B
where the change of the gate signal is small.
[0094] As such, according to exemplary embodiments, since the gate
on pulses having the same (or substantially the same) waveform or
the same (or substantially the same) level may be output at a
plurality of gate driving circuits 450 despite relative differences
in their spatial positioning. As such, it is possible to prevent
image quality from being deteriorated according to a deviation of
the waveforms of the gate on pulses.
[0095] Another display apparatus, according to exemplary
embodiments, is described in association with FIG. 8. In this
manner, it is noted that similarly configured constitute components
of the display apparatus of FIG. 8 are similarly numbered as in the
display apparatus of FIG. 1. To avoid obscuring exemplary
embodiments described herein, repetitive description of similarly
numbered constituent components has been omitted.
[0096] FIG. 8 is a block diagram of a display apparatus, according
to exemplary embodiments.
[0097] Referring to FIG. 8, a display apparatus includes a display
panel 300, a gate driver 400, a data driver 500, a driving voltage
generator 700, and a gate on voltage modulator 800. The display
apparatus also includes a signal controller 600. As previously
mentioned, the gate driver 400, the data driver 500, the signal
controller 600, the gate on voltage modulator 800, and/or the
driving voltage generator 700 may be implemented via one or more
general purpose and/or special purpose components, such as one or
more discrete circuits, digital signal processing chips, integrated
circuits, application specific integrated circuits,
microprocessors, processors, programmable arrays, field
programmable arrays, instruction set processors, and/or the
like.
[0098] The gate driver 400 of the display apparatus may be embedded
in the gate on voltage modulator 800. Namely, at least one gate
driving circuit 450 included in the gate driver 400 may include the
gate on voltage modulator 800 as described above to directly
generate a modulated gate on voltage VGPM in the gate driving
circuit 450. Accordingly, since the modulated gate on voltage VGPM
is not influenced by a signal delay due to the resistor(s) of the
signal wiring line SL when a down pulse of the modulated gate on
voltage VGPM is generated, pulse waveforms and levels of the
modulated gate on voltages VGPM generated by the respective gate
driving circuits 450 may be the same (or substantially the same) as
each other.
[0099] The gate driver 400 of FIG. 8 is described in more detail in
association with FIG. 9, as well as the waveform diagram of FIG.
5.
[0100] FIG. 9 is a block diagram of a gate driving circuit of a
driving device of the display apparatus of FIG. 8, according to
exemplary embodiments.
[0101] Referring to FIG. 9, a gate driving circuit 450 includes the
gate on voltage modulator 800 and a gate signal generator 430
connected thereto.
[0102] The gate on voltage modulator 800 may include a modulation
controller 810, a first transistor M1, a second transistor M2, and
an amplifier 820.
[0103] The modulation controller 810 is configured to receive a
modulation control signal KB from the signal controller 600 to,
thereby, control the first and second transistors M1 and M2.
[0104] The first transistor M1 and the second transistor M2 may be
field effect transistors FET.
[0105] A source terminal of the first transistor M1 is connected to
a gate on voltage Von, a gate terminal is connected to the
modulation controller 810, and a drain terminal is connected to the
gate signal generator 430, as well as the drain terminal of the
second transistor M2. The first transistor M1 may be an n-type
transistor.
[0106] A drain terminal of the second transistor M2 is connected to
the drain terminal of the first transistor M1, a gate terminal is
connected to the modulation controller 810, and a source terminal
is connected to an output terminal of the amplifier 820. The second
transistor M2 may be a p-type transistor.
[0107] The amplifier 820 includes a non-inversion input terminal
(e.g., a positive "+" terminal) configured to receive a low voltage
Vlow and an output terminal connected to the source terminal of the
second transistor M2, and an inversion input terminal (e.g., a
negative "-" terminal) of the amplifier 820 is connected to an
output terminal to feedback an output voltage. A variable resistor
RC may be connected between the second transistor M2 and the output
terminal of the amplifier 820.
[0108] An operation of the gate on voltage modulator 800 is
described in more detail in association with FIGS. 5-9.
[0109] The first transistor M1 is conducted (e.g., "turned-on") and
the second transistor M2 is interrupted (e.g., "turned-off") while
the modulation control signal KB input from the signal controller
600 is at a high level. As such, the gate on voltage Von is output
to the gate signal generator 430 via the first transistor M1. When
the modulation control signal KB is changed to a low level, the
first transistor M1 is interrupted (e.g., "turned-off") and the
second transistor M2 is conducted (e.g., "turned-on"). As such, a
voltage charged in an equivalent capacitor (not illustrated)
connected to the drain terminal of the first transistor M1 is
discharged to the source terminal of the second transistor M2 and a
down pulse of the modulated gate on voltage VGPM is generated as
illustrated in FIG. 5 and, thereby, output to the gate signal
generator 430. A slope of the down pulse of the modulated gate on
voltage VGPM may be controlled via adjusting the variable resistor
RC of the gate on voltage modulator 800.
[0110] As described above, the gate signal generator 430 is
configured to receive the generated modulated gate on voltage VGPM
to, thereby, generate the plurality of gate signals VG1_1-VGa_1 as
described above, as well as to output the generated plurality of
gate signals VG1_1-VGa_1 to the plurality of gate lines G1_1-Ga_1
connected to the gate driving circuit 450.
[0111] While certain exemplary embodiments and implementations have
been described herein, other embodiments and modifications will be
apparent from this description. Accordingly, the invention is not
limited to such embodiments, but rather to the broader scope of the
presented claims and various obvious modifications and equivalent
arrangements.
* * * * *